1,720,956 research outputs found
The Knapsack Sequencing Problem: Computational Complexity and Mechanism Design
Get PDFThis paper introduces a combinatorial optimisation problem that we call the knapsack sequencing problem (KSP). KSP arises when the server in a sequencing problem is constrained to work in fixed-duration shifts. Each shift can be viewed as a knapsack, but unlike standard knapsack or bin-packing problems, KSP incorporates a temporal structure that distinguishes early and late shifts. The main challenge lies not in incentivising truth-telling but in algorithmically identifying the optimal partition of agents into shifts; a challenge compounded by the fact that KSP is strongly NP-hard, with the decision version being strongly NP-complete. We propose necessary conditions that efficient sequencing rules must satisfy, which help reduce the search space for feasible partitions. We show that the Vickrey–Clarke–Groves (VCG) mechanism, using the efficient sequencing rule and VCG transfers, is strategy-proof for KSP. We establish the existence of first-best mechanisms—mechanisms that are efficient, strategy-proof, and budget balanced—for a subclass (unit-capacity) of KSP requiring n shifts to serve n agents. We also show, via a three-agent example, that when budget balance is imposed together with efficiency, strategy-proofness may fail. This research highlights the difficulties in extending classical sequencing results to settings with shift constraints and contributes both theoretical insights and algorithmic considerations relevant to resource allocation mechanisms
Mechanism Design for Queueing with Capacity-Constrained Shifts
Get PDFWe study a single-server queue with fixed-length shifts where service of unit length jobs is non-pre-emptive; residual time shorter than one job, namely fractional part of , at boundaries is lost. Agents have constant private unit waiting costs. The efficient rule partitions agents into feasible shifts, orders shifts by the sum of members' costs, and orders agents within each shift by their costs. We show, by \citet{Holmstrom} and \citet{Suijs} type arguments, that only Vickrey-Clarke-Groves (VCG) transfers implement efficiency in dominant strategies. We then delineate when efficiency and DSIC implementation can be combined with budget balance (first-best mechanisms). If shifts are of unit-capacity ( is non-integral (so each shift can host at least two agents but leaves residual slack), no first-best mechanism exists. The proof uses a the cubical-array lemma of \citet{Walker} adapted to our setting
Mechanism Design for Queueing with Capacity-Constrained Shifts
No full textWe study a single-server queue with fixed-length shifts where service of unit length jobs is non-pre-emptive; residual time shorter than one job, namely fractional part of , at boundaries is lost. Agents have constant private unit waiting costs. The efficient rule partitions agents into feasible shifts, orders shifts by the sum of members' costs, and orders agents within each shift by their costs. We show, by \citet{Holmstrom} and \citet{Suijs} type arguments, that only Vickrey-Clarke-Groves (VCG) transfers implement efficiency in dominant strategies. We then delineate when efficiency and DSIC implementation can be combined with budget balance (first-best mechanisms). If shifts are of unit-capacity ( is non-integral (so each shift can host at least two agents but leaves residual slack), no first-best mechanism exists. The proof uses a the cubical-array lemma of \citet{Walker} adapted to our setting
The Knapsack Sequencing Problem: Computational Complexity and Mechanism Design
No full textThis paper introduces a combinatorial optimisation problem that we call the knapsack sequencing problem (KSP). KSP arises when the server in a sequencing problem is constrained to work in fixed-duration shifts. Each shift can be viewed as a knapsack, but unlike standard knapsack or bin-packing problems, KSP incorporates a temporal structure that distinguishes early and late shifts. The main challenge lies not in incentivising truth-telling but in algorithmically identifying the optimal partition of agents into shifts; a challenge compounded by the fact that KSP is strongly NP-hard, with the decision version being strongly NP-complete. We propose necessary conditions that efficient sequencing rules must satisfy, which help reduce the search space for feasible partitions. We show that the Vickrey–Clarke–Groves (VCG) mechanism, using the efficient sequencing rule and VCG transfers, is strategy-proof for KSP. We establish the existence of first-best mechanisms—mechanisms that are efficient, strategy-proof, and budget balanced—for a subclass (unit-capacity) of KSP requiring n shifts to serve n agents. We also show, via a three-agent example, that when budget balance is imposed together with efficiency, strategy-proofness may fail. This research highlights the difficulties in extending classical sequencing results to settings with shift constraints and contributes both theoretical insights and algorithmic considerations relevant to resource allocation mechanisms
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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